Callus Induction, In vitro Shoot Development and Somaclonal Variations in Cotton

Abstract

Callus induction and regeneration were studied in the two Turkish cotton varieties (Nazilli 84-S and Sahin 2000) possessing different sensitivity levels to salt. Also, the rate of polymorphisms was investigated using random amplified polymorphic DNA (RAPD) in the plant samples obtained from the shoot tip and node cultures. The cotyledon and hypocotyl explants gave better response in terms of callus induction when compared with the root explants. Hypocotyl explants were cultured in the Murashige-Skoog medium supplemented with 0.1 mg/l kinetin, 0.1 mg/l 2.4-D and 0.1 mg/l IAA and 77% and 84% callus induction was observed in Nazilli 84-S and Sahin 2000 cultivars, respectively. When MS medium was supplemented with various plant growth regulators, callus induction from the cotyledon and hypocotyl explants were observed. However, plant regeneration was not evident. When, 0.1 mg/l TDZ and 0.1 mg/l kinetin were added to the MS medium, 100% explant response was seen in both cultivars in the shoot tip cultures. Morever, in the cotyledonary nodes grown in the MS medium with the addition of 0.25 mg/l kinetin, the explant response was 86% and 68% for Nazilli 84-S and Sahin 2000, respectively. Genetic variation in the plants produced by direct regeneration of the shoot-tip and node cultures was determined via the RAPD technique. Genetic similarity was found to be highly similar for the both cultivars used in this study. The plants of Nazilli 84-S and Sahin 2000 had 9399% and 94-99%, respectively

Keywords

• Shoot tip culture, node culture, genetic similarity, RAPD